I wouldn't touch Starmer with a barge pole. He's completely untrustworthy

In the first of a new weekly series in which we ask a public figure to take us on a walk of significance, Rachel Sylvester, our political editor strolls through London's Stoke Newington with Zack Polanski. The leader of the Greens talks about tax hikes, leaving Nato and why former Labour politicians are welcome to join his party

- Rachel Sylvester

Zack Polanski is a former hypnotherapist and actor who is gay, Jewish and vegan, with crooked teeth. He is wearing secondhand clothes - an old Uniqlo suit that he bought on Vinted - and turquoise fake leather Dr Martens. He has not flown for more than a decade and he does not drive. His guilty pleasure is vegan jaffa cakes: "Yes, they do exist and they're bloody gorgeous," he says.

At the age of 43, the Green party leader in England and Wales is the opposite of a conventional politician but, with his promise to "make hope normal again", he is taking Westminster by storm. Since he was elected to the role in September, the Greens have leapfrogged over the Liberal Democrats and are tied in third place with the Conservatives in the polls.

Last week YouGov put them on 17%, just 2 percentage points behind Labour. Among young people, they are the most popular party. As progressive voters turn away from Keir Starmer's government, the Greens now have 170,000 members - more than both the Tories and the Lib Dems. Polanski's Instagram account has had at least 33m views in the past 30 days.

Some in Labour mutter that it is all a "Cleggmania"-style bubble - a reference to the once-popular former Lib Dem leader Nick Clegg - but Polanski hopes that his brand of leftwing eco-populism will be a match for Nigel Farage and Reform UK. Certainly, Polanski is a good communicator. Some have compared him to Zohran Mamdani, the recently elected Democratic mayor of New York. Already Polanski is accelerating the fragmentation of the traditional party system. So is he serious? And will his efforts to reshape politics for a new age be tarnished by association with the old hard left?